Ankle Brachial Index Utility: Prevalence of Peripheral Arterial Disease and Risk Factors among Diabetic Patients Attending an Outpatient Clinic in Northwestern Tanzania

Background: Peripheral arterial disease (PAD) is a disease of public health significance, ranging from asymptomatic to symptomatic presentation. The impact of PAD may be profound in many low to middle income countries (LMICs) where walking a substantial distance is required to obtain the daily basic needs. This study was conducted to determine prevalence of peripheral arterial disease and risk factors among diabetic patients attending an outpatient clinic in Northwestern Tanzania. Methods: A descriptive cross-sectional study carried out among adult patients attending a Diabetic Outpatient Clinic in Mwanza Tanzania. Demographic data and risk factors for PAD were recorded on a pretested questionnaire. Ultrasound guided ABI was measured using a standard mercury sphygmomanometer. Edinburgh Claudication Questionnaire (ECQ) was compared to the Fontaine Classification in PAD detection. Chi-square test, Fisher’s exact test and logistic regression analyses were used to test for significance of association between independent and dependent variables with a p-value (p) <0.05 considered statistically significant. Receiver operator characteristic (ROC) curve analysis was also utilized to determine performance of ABI against clinical grading of PAD. Results: A total of 386 participants were enrolled in this study with a mean age of 60.0 ± 12.3 years. There was a significant association between an abnormal ABI with HbA1c, family history of cardiovascular diseases, hypertension, cigarette smoking and claudication (p=0.04 to <0.001). Claudication [aOR (95% CI) = 6.30 (3.14-12.64), p<0.001] was independently associated with an abnormal ABI. Prevalence of PAD was slightly lower based on clinical grading of PAD (30.8%) in comparison to an abnormal ABI respectively (34.5%). ABI had a sensitivity of 64.7%, specificity of 79.0%, positive predictive value of 57.9%, negative predictive value of 83.4%, accuracy of 74.6%. Area under the ROC curve of ABI was 0.72 against clinical grading of PA